A 50-year-old man with motor neurone disease presents to hospital with respiratory distress following two (2) days of fever and malaise. He is alert and anxious, and an arterial blood gas performed on oxygen (8L/min semi-rigid mask) revealed PaO2 45 mmHg, PaCO2 65 mmHg, pH 7.36 and HCO3 36 mmol/L. He has used a motorised wheelchair for three (3) years but continues to work as an accountant. His attentive wife states that they have discussed mechanical ventilation and are keen for him to receive full Intensive Care support.

• How will you approach the issue of mechanical ventilation in this man?

College Answer

A decision about mechanical ventilation is necessary but is not urgently required. Time should be taken to talk through the potential problems, and ensuring that the patient and wife are aware of the actual implications of ventilation (likely need for and potential complications of intubation & tracheostomy, difficult or impossible wean, prolonged ICU, long term hospital and home ventilation [if available!]). Discussion should include what factors are likely to be reversible (including time frame). Other input may be appropriate and should be sought (parent unit, treating doctors, neurologists, pastoral care). The issues of consent (who and for what must be clarified). After detailed discussion, patient and wife (if appropriate surrogate) should be able to decide.

Discussion

In discussing mechanical ventilation with a person who is "keen" on it but who will likely end up dependent on it for a long term, the main concepts which govern medical ethics need to be considered:

Consider beneficence: is the therapy in the patient's best interest? In this case, mechanical ventilation is acutely life saving, and the patient has not indicated otherwise, so - yes.

Consider non-maleficience: is the therapy going to burden the patient? In this case, mechanical ventilation will never be a "short trial" and a tracheostomy is a real possibility, but in the short term mechanical ventilation will likely be well tolerated.

Consider fidelity: the patient needs to be given a honest breakdown of exactly what the therapy will require, and what the goals of it will be. One might involve people who organise home ventilation to discuss this issue with the patient. A discussion of tracheostomy is also important.

Consider utility (rather than futility): is the therapy going to be helpful? As far as what "helpful" means, one needs to defer to the values of the patient and their family as well as to the objective physiological effectiveness of the therapy.

Invoke the principle of autonomy. The outcome achieved by this therapy: is this outcome one which the patient would find satisfactory? A honest discussion of what long-term ventilation via tracheostomy looks like needs to take place after the acute physiological disaster has been managed.

Consider social justice as the last and least important consideration; are the needs of the community served best if this treatment is to go ahead?

Decisions can then be made to limit or withdraw the therapy if any of the following conditions are satisfied

The therapy is considered unlikely to succeed on grounds of basic physiology (i.e. it would be scientifically impossible for it to achieve the intended goals)

The therapy is known to fail in the vast majority of attempts under these conditions, and the attempt has known and serious adverse consequences

The therapy would (if successful) lead to a quality of life which is unacceptable to the patient, or (if the patient or family cannot comment) which would lead to a quality of life which "falls well below the threshold considered minimal by general professional judgment"

The therapy leads to the preservation of a state which is unacceptable for the patient, eg. the therapy merely preserves unconsciousness and dependence on intensive medical care.

There are parties (including other medical professionals and important figures from the patient's family) who agree that the cost or outcome of the therapy would be unacceptable to the patient.